This sticky is here to inform people about the impact of having more VRAM in your machine.

Rule about VRAM (video memory): If you have more VRAM in your machine it will be able to play games at higher resolution textures slightly faster (I.E. DOOM 3 at 1920x1200).

However: The upgrade is almost never worth the money when buying a new mac (for games atleast) I.E. extra $500 for new MBP, and your overall performance improvement will be negligible at best. Any speed increase you see on a mac with the higher-end card will most likely be due to the higher CPU speed and/or more RAM.

What is VRAM?
VRAM is Video RAM. It's memory that resides on the graphics card and is dedicated for the card's use. It is often faster than regular system memory, and more importantly, its close proximity to the graphics processing unit (GPU) on the graphics card allows for quick access to data stored in this memory for rendering graphics scenes.
What is it used for?
It's used for any data that the graphics card needs to render a scene in a game: vertex data for models, textures, shader textures, a buffer for the pixel data that will be sent to the monitor.
So is more better?
Up to a point, yes. The general rule of thumb with RAM of any sort is that you will see an improvement up until you have enough, then there will be no improvement after that. This is because data stored in the VRAM is able to be quickly accessed by the GPU, while it takes longer to access the same data from main memory. If there's not enough room for all the data it needs in the VRAM, then it needs to store part of it in the computers main RAM, which takes longer to retrieve, and therefore slows down rendering times while the GPU waits for the extra data. So unlike a processor, where more speed is almost always an improvement, adding more RAM only helps until you've got enough to hold the data you need, and the rest is just wasted space.
Will more VRAM improve my framerates?
Maybe. It depends on the situation. More VRAM does not make the GPU process graphics data any faster, only access it faster when it needs it. So if you're trying to run a game at a high resolution like 1920x1200, that means that in the end, the GPU has to process 2,304,000 pixels, and the speed it can do that is ultimately limited by the capability of the GPU chip, and not by the amount of VRAM it has available. If the GPU is too slow to run a game at the resolution you're running it at, more RAM won't help.

However, since VRAM size determines the amount of data stored locally to the GPU, it will affect how much data can be involved and still run at the same speed. So you can use higher quality textures, more anti-aliasing, and more shaders (which are stored as images, similar to textures) at the same resolution and still get a good framerate because the card can hold all that data locally, and doesn't have to wait to fetch it from the main RAM. It's worth noting that the pixel buffer is stored in the VRAM - a higher resolution will increase the size of the buffer, which could then push other data out to the main memory.

So how come my card with (e.g.)128Mb doesn't run this game well!? It's an 128Mb card, and the requirements for the game are only (16/32/64/whatever)Mb!?
See the above answer. It most likely because the card in question pairs a slower or less capable GPU with a lot of memory. If the GPU is too slow to process everything going on in the game, then it doesn't matter that it has lots of memory. The main reason why this tends to happen is because the graphics card makers have lots of different models for any given generation, all of which have different capability. Add to this the fact that cards of different generations are available at any given time, and it can be confusing for people trying to figure out which card is the best to buy, or whether their card is as good as the one listed on the game box. Because of this, they quite often use 'graphics card with x-Mb VRAM' as a requirement for a game, or feature the amount of memory prominently on the box for a graphics card. In theory, because the amount of memory has been going up with each generation of graphics cards, this gives you a general idea of the capability of a card, but it's problematic.

The amount of memory on the card actually gives no idea what the capability of the GPU on that card is. To make matters more confusing, the graphics card makers will sometimes re-release an older GPU with more VRAM as a new card.

So how do I figure out what a good graphics card to buy is? / How can I figure out if my graphics card can run a game?
Instead of looking at the VRAM, look at the model number. There are lots of them, but in general you have the generation of video card, followed by the class of card, usually followed by a suffix. It can get confusing - but the model number gives a better general idea of capability. For example, the current (as of this writing) generation of nVidia cards are numbered as such: 8800, 8600, 8500, with the '88' series being the high-end, '86' as the mid-range, and lower than that as budget cards. The previous generation was similar: 7800, 7600, etc. Usually between generations of GPU, they come out with new cards that are using the same GPU, but running at a faster speed, for example, the 7900 series in between the 7800 and the 8800. It's expected that a 'refresh' of the current generation will be released with a similar naming scheme.

Try doing a search for a reviews and benchmarks of a particular card. The reviewers will quite often compare it with a few different cards, and use several games to test it, which gives both an idea of how that card compares with others, and how it runs various games. Here are some good review sites:

Places to find benchmarks:
www.barefeats.com (Mac-specific)
www.anandtech.com (PC - more cards than exist on the Mac, but it gives a good idea of how they compare to each other)
www.guru3d.com (similar to Anandtech)
www.tomshardware.com (ditto)
as always, Google is your friend.

What is VRAM?
VRAM is Video RAM. It's memory that resides on the graphics card and is dedicated for the card's use. It is often faster than regular system memory, and more importantly, its close proximity to the graphics processing unit (GPU) on the graphics card allows for quick access to data stored in this memory for rendering graphics scenes.
What is it used for?
It's used for any data that the graphics card needs to render a scene in a game: vertex data for models, textures, shader textures, a buffer for the pixel data that will be sent to the monitor.
So is more better?
Up to a point, yes. The general rule of thumb with RAM of any sort is that you will see an improvement up until you have enough, then there will be no improvement after that. This is because data stored in the VRAM is able to be quickly accessed by the GPU, while it takes longer to access the same data from main memory. If there's not enough room for all the data it needs in the VRAM, then it needs to store part of it in the computers main RAM, which takes longer to retrieve, and therefore slows down rendering times while the GPU waits for the extra data. So unlike a processor, where more speed is almost always an improvement, adding more RAM only helps until you've got enough to hold the data you need, and the rest is just wasted space.
Will more VRAM improve my framerates?
Maybe. It depends on the situation. More VRAM does not make the GPU process graphics data any faster, only access it faster when it needs it. So if you're trying to run a game at a high resolution like 1920x1200, that means that in the end, the GPU has to process 2,304,000 pixels, and the speed it can do that is ultimately limited by the capability of the GPU chip, and not by the amount of VRAM it has available. If the GPU is too slow to run a game at the resolution you're running it at, more RAM won't help.

However, since VRAM size determines the amount of data stored locally to the GPU, it will affect how much data can be involved and still run at the same speed. So you can use higher quality textures, more anti-aliasing, and more shaders (which are stored as images, similar to textures) at the same resolution and still get a good framerate because the card can hold all that data locally, and doesn't have to wait to fetch it from the main RAM. It's worth noting that the pixel buffer is stored in the VRAM - a higher resolution will increase the size of the buffer, which could then push other data out to the main memory.

So how come my card with (e.g.)128Mb doesn't run this game well!? It's an 128Mb card, and the requirements for the game are only (16/32/64/whatever)Mb!?
See the above answer. It most likely because the card in question pairs a slower or less capable GPU with a lot of memory. If the GPU is too slow to process everything going on in the game, then it doesn't matter that it has lots of memory. The main reason why this tends to happen is because the graphics card makers have lots of different models for any given generation, all of which have different capability. Add to this the fact that cards of different generations are available at any given time, and it can be confusing for people trying to figure out which card is the best to buy, or whether their card is as good as the one listed on the game box. Because of this, they quite often use 'graphics card with x-Mb VRAM' as a requirement for a game, or feature the amount of memory prominently on the box for a graphics card. In theory, because the amount of memory has been going up with each generation of graphics cards, this gives you a general idea of the capability of a card, but it's problematic.

The amount of memory on the card actually gives no idea what the capability of the GPU on that card is. To make matters more confusing, the graphics card makers will sometimes re-release an older GPU with more VRAM as a new card.

So how do I figure out what a good graphics card to buy is? / How can I figure out if my graphics card can run a game?
Instead of looking at the VRAM, look at the model number. There are lots of them, but in general you have the generation of video card, followed by the class of card, usually followed by a suffix. It can get confusing, but the model number gives a better general idea of capability. For example, the current (as of this writing) generation of nVidia cards are numbered as such: 8800, 8600, 8500, with the '88' series being the high-end, '86' as the mid-range, and lower than that as budget cards. The previous generation was similar: 7800, 7600, etc. Usually between generations of GPU, they come out with new cards that are using the same GPU, but running at a faster speed, for example, the 7900 series in between the 7800 and the 8800. It's expected that a 'refresh' of the current generation will be released with a similar naming scheme.

Try doing a search for a reviews and benchmarks of a particular card. The reviewers will quite often compare it with a few different cards, and use several games to test it, which gives both an idea of how that card compares with others, and how it runs various games. Here are some good review sites:

www.barefeats.com (Mac-specific)
www.anandtech.com (PC - more cards than exist on the Mac, but it gives a good idea of how they compare to each other)
www.guru3d.com (similar to Anandtech)
www.tomshardware.com (ditto)
as always, Google is your friend.

Those benchmarks seem to just go by the bottom line of how much average frame rate you get when you run a timedemo or something. But one thing that more VRAM helps isn't really about that. So let's say you are running a typical level in Doom 3 for example and you get to a door to a new room and your card doesn't have enough to cope with the amount of textures being thrown around. It could run at a good frame rate until you open a door and then it pauses and hitches as the new textures\etc. load which is called "texture thrashing". That is until it's done and then it's fine again until you reach another door and so on. So just focusing on the bottom line doesn't really tell people what kind of benefits or lack of benefits they would get with more VRAM. But it does paint a picture of the overall performance at specific settings. In the situation if you don't have enough VRAM you'd have to run with lower texture detail settings unless you don't mind texture thrashing. That's in addition to being able to run the game at higher resolutions with AA, AF, etc. That's also just for games.. I noticed that HD Video also needs more VRAM. Which should be obvious since you are loading a bunch of high resolution pictures to your GPU a second.

Also I would agree that when choosing a card looking at the model number is probably the most important thing but VRAM is another thing to look at after that. But of course it's not the only thing to look at and it's not the most important thing since it can be misleading since lower models can have more VRAM. So I'm not trying to perpetuate the myth that VRAM trumps all in case anyone jumps to that conclusion.

a lot of correct information here, but you gave your answer yourself and don't even seem see it!

Some games might demand more textures, shaders and AA than the 128MB the card provides. What happens then is that the performance will break down. I don't care about ultra high resolutions, but I care about what todays games demand using reasonable settings, who knows. I know that the only thing happening will be the movement to the system RAM. What I wanna know is what happens then.

A comparison done on a healthy testbed won't hurt and will end discussions once and for all. I've known all the websites you listed but in years I can't remember a single instance when they properly addressed this question.
I also know there is no analytical answer to this since every game will address the lack of memory differently, but an empirical answer will surely satisfy most of the people to the point where they can spend their well earned money for something they truly want!

Especially since it's wrong - the capability of the GPU has more to do with what resolution you can run the game at.

If we substitute 'texture resolution' then it's correct.

But yes, I've made many a post correcting the misconceptions, I wouldn't mind a sticky.

In this thread offered up by Lemon Lime the difference between 128VRAM and 256VRAM performance is negligible frame rate differences at the same resolution and I'm surprised. Why bother to pay extra for the 256VRAM?

[Edit - Why are you discussing one thread in another thread? I've moved your post into the topic you are discussing - tBC]

In this thread offered up by Lemon Lime the difference between 128VRAM and 256VRAM performance is negligible frame rate differences at the same resolution and I'm surprised. Why bother to pay extra for the 256VRAM?

for games, there is no reason to bother. If you are hardcore video editor who spends the majority of his day in Final Cut/Motion, you will need the extra VRAM, because Motion uses the Graphics card to cache some stuff. This is really the only app that the extra VRAM really does greatly effect the quality of your expierence (though I may be wrong). Not to mention the extra cpu speed and HD count for part of the price.

for games, there is no reason to bother. If you are hardcore video editor who spends the majority of his day in Final Cut/Motion, you will need the extra VRAM, because Motion uses the Graphics card to cache some stuff. This is really the only app that the extra VRAM really does greatly effect the quality of your expierence (though I may be wrong). Not to mention the extra cpu speed and HD count for part of the price.

The tendency of video card manufacturers is to increase VRAM over time. I'd say 128 or 256 is the average.

id say that 128 is the low end standard these days, with 256 being expected of a mid range card, 320 being the Nvidia odd ball of the moment, 512 being high end, and 1Gb being pointless for all but a small few..

and im talking about the here and now, not next year, or when the game based on Idtech5 comes out. thats why im saying that 1gb of VRAM is pointless for most people. Anyway, i can only think of 2 GPUs which have 1Gb of VRAM, and theyre both X2900HDs...

The tendency to constantly increase them is largly for the same reasone they make it the hilight point of the video card.

Average Joe who wants a new vid card: oooooooo 512 VRAM! thats a bigger number than 256!

even though the 256 card could be potentially faster.

Why are you so sarcastical about it? It is the same GPU and yes, you're right, a GF8 with half the RAM could be faster then a GF7, but there is a sweet spot for everything and from experience I know, that because of one factor, performance can drop beyond the point of enjoyment easily!

Well of course I consider 1GB of VRAM absolutely ridiculous for now too!! 128MB at normal resolutions (not even the native one of the display) is definitely not too much though either, especially when using AA and AF (you said that yourself). Why don't we wait for some numbers other than the Doom3 engine under OSX (where drivers seem suboptimal thus performance limited by the CPU alone, it seems). I'm the last one caring about numbers to impress other people, I only care about the result and if that changes significantly (around 100%), then I will listen before I spend the money!

Like I said having say, 256MB isn't about the bottom line FPS score. It's more about being able to handle the amount of xyx in the game at a particular setting during the game so it doesn't swap to RAM.

*NOTE: I corrected the labels. The first posting had Doom 3 and Quake 4 results switched.

Though few will play 3D games on a MacBook Pro with 128M or 256M at Ultra Quality --- or with FSAA enabled at native resolution, this clearly demonstrates that there is a threshold at which the MBP with the larger VRAM gains a significant advantage.

Though few will play 3D games on a MacBook Pro with 128M or 256M at Ultra Quality --- or with FSAA enabled at native resolution, this clearly demonstrates that there is a threshold at which the MBP with the larger VRAM gains a significant advantage.

This confirms my statement that at extreme texture resolutions, the VRAM does make a differnce. However, I can not help myself but to say that those bench marks are off. there is NO WAY that you were get 4 FPS on DOOM 3, reguardless of wether its on ultra or not. You should be testing this without FSAA to elminate that variable.

This confirms my statement that at extreme texture resolutions, the VRAM does make a differnce. However, I can not help myself but to say that those bench marks are off. there is NO WAY that you were get 4 FPS on DOOM 3, reguardless of wether its on ultra or not. You should be testing this without FSAA to elminate that variable.

Sorry. I goofed. I labeled the Doom 3 results as Quake 4 and vice versa. I corrected the posting above.

The 4 fps result was for Quake 4 at 1440x900 Ultra Quality but NO FSAA. I was surprised by that result, too. I ran each setting twice and recorded the fastest of the two runs.

The runs with FSAA enabled were at High Quality. You can imagine why I didn't use *both* Ultra Quality *and* FSAA 4X. I gave up on that scenario when I ran Doom 3 with both enabled at 1280x800 on the 128M machine and got 7 fps.